API Reference

The Helios API serves the same data the platform runs on, from the same database that grades it. Base URL: https://api.helios.markets. This page is integration contract v1 — changes to it are dated, and breaking changes are announced with a deprecation window.

Authentication

Every keyed request carries your API key in the X-API-Key header. Your key is issued from your account page and inherits your subscription tier. Verify identity and tier at any time with GET /v1/whoami.

Start here

GET /v1/api_guide is the machine-readable guide: it describes each layer, what its status labels mean, and what to build on. It is public and always current — treat it as the living half of this contract.

Endpoints by tier

• Public, no key — /health · the track record family: /v1/track_record, /aggregate, /calls, /trades, /day_card, /executor, /public · /v1/intel/brief_teaser · /v1/courts (every graded record with n and p-values, live) · /v1/api_guide
• Tier 1+ — /bars/{symbol} · /history/regime/{symbol} · /history/stats
• Tier 2+ — /v1/signals/current (response depth scales with tier) · /v1/premarket · /v1/intel · /v1/intel/brief · /v1/organs · /v1/iv_matrix/{symbol} · /v1/block_trades · /v1/qualified_signal · /v1/paper_trades · /history/flow/{symbol} · /history/strikes/{symbol}
• Tier 3 — /history/gex/{symbol} · /history/dex/{symbol} · /history/hwaves/{symbol} · /history/mm/{symbol} · /v1/iv_smile/{symbol} · /v1/orderflow/{symbol} (per-minute tape, 1-minute poll fidelity) · /v1/exports/{dataset} (graded court datasets as JSON or CSV: morning_signal, day_card, mirror_trades, overnight_card)

Polling and staleness

Poll live endpoints every 10–30 seconds during market hours; history endpoints accept since/until/limit and should be fetched incrementally. Payloads carry timestamps and staleness flags — honor them. A stale flag means the platform itself is not trusting that reading; neither should your system.

Streaming

A Tier 3 (Institutional) feature as of September 10, 2026 — lower tiers are closed with code 4403. Connect to wss://ws.helios.markets/?api_key=YOUR_KEY. On connect you receive a hello message listing your allowed channels; subscribe with {"type":"subscribe","channels":["signals.current"]}. A heartbeat arrives every 5 seconds. Channels: signals.current pushes the full signal payload (same shape and tier depth as the REST endpoint) roughly every 5 seconds; signals.regime emits an event only when a symbol changes dealer regime. Unauthorized connections close with code 4401. Reconnect with backoff; the stream carries the same staleness flags as REST — honor them.

Versioning and deprecation

Paths are stable. When a path is renamed, the old path serves as an alias for at least 30 days and the dates are recorded here. Current entries: /history/elliott/* is deprecated in favor of /history/hwaves/*; the alias retires 2026-10-01.

What is deliberately not served

Signal construction internals, raw model votes, and fund-side data are never served on any key at any tier. Grading is fully transparent — see the Grading Standards — methodology is not.

Fair use

Keys are per-account and rate limits are enforced per tier. If your use case needs more, talk to the desk — do not work around the limits.